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  • 1
    Electronic Resource
    Electronic Resource
    Conformational effects in the chemical ionization spectra of derivatives of isomeric 2,3-dimethyl-1,4-cyclopentanediolsStudies in Organic Mass Spectrometry XXVIII. Part XXVII: F. Van Gaever, J. Monstrey and C. C. Van de Sande, Org. Mass Spectrom. 12, 200 (1977) (1977)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 12 (1977), S. 531-535 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The chemical ionization mass spectra of the trimethylsilyl and methylboronate derivatives of some isomeric 2,3-dimethyl-1,4-cyclopentanediols have been determinded using methane and isobutane as reagent gases. The degree of loss of TMSOH or CH3B(OH)2 appears to be strongly dependent upon the stereochemistry of the 2,3-dimethyl-1,4-cyclopentanediol moiety and permits differentiation between the structural isomers. The results obtained from the chemical ionization (isobutane) spectra of the methylboronates are in excellent agreement with those derived from infrared data.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210120810
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  • 2
    Electronic Resource
    Electronic Resource
    Structural characterization of mono- and bisphosphonium salts by fast atom bombardment mass spectrometry and tandem mass spectrometry (1993)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 28 (1993), S. 71-82 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Positive-ion fast atom bombardment (FAB) mass spectra are reported for a representative series of mono- and bisphosphonium halides derived from triphenylphosphine. The mass spectra of the monoalkyltriphenylphosphonium salts typically contain abundant intact cations that can be used to establish the cationic relative molecular mass and diagnostic fragment ions that allow the characterization of structural subgroups. Depending on the functional group substitution on the alkyl group, additional fragment ions are observed which are formed by loss of small neutral molecules from the intact cation and that can be used for the differentiation of isomeric phosphonium salts. Molecular dication are typically observed in the FAB mass spectra of the bisphosphonium salts when they are analysed in 3-nitrobenzyl alcohol. In addition, production of singly charged ions by clustering with a counter ion, decomposition involving removal of one of the charge centres and one-electron reduction are generally observed. Structurally diagnostic fragments are also obtained. The fragmentation pathways of the ions derived from the phosphonium salts were elucidated by precursor ion and product ion tandem mass spectrometric experiments. For the phosphonium salts containing a long-chain hydrocarbon alkyl group, high-energy collision-induced decomposition of the intact cation is needed to obtain unambiguous structural information.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210280204
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  • 3
    Electronic Resource
    Electronic Resource
    Studies in organic mass spectrometry. XXPart XIX: Ref. 1. - Stereospecificity in hydrogen transfer reactions in mass spectra of TMS derivatives of some 2,3-dialkyl-1, 4-cyclopentanediols (1974)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 9 (1974), S. 1182-1187 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of TMS ethers of 2,3,-dialkyl-1,4-cyclopentanediols having a 2′-carboxyl group or 2′-double bond in one of the sidechains, display a stereospecific rearrangement process. A mechanism is proposed to account for this stereospecificity.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210091205
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  • 4
    Electronic Resource
    Electronic Resource
    Selected ion monitoring analysis of monoamine metabolites in cerebrospinal fluid. Application to the study of in vivo effects of α2-antagonists (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 675-682 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The technique of isotope dilution mass spectrometry has been used for the measurement of biogenic amine metabolites in cerebrospinal fluid (CSF). CSF samples were collected from rabbits treated with α2-antagonists. The aim of our study was to determine the specificity of these drugs on the central nervous noradrenergic, dopaminergic and serotonergic activity as measured by the release of corresponding monoamine metabolites. 3-Methoxy-4-hydroxyphenylethylene glycol (MHPG) and vanilmandelic acid (VMA) were used as parameters for the noradrenergic activity, whereas homovanillic acid (HVA) and 5-hydroxyindole-3-acetic acid (5-HIAA) were employed to follow the dopaminergic and serotonergic activity, respectively. For the measurement of the biogenic amine metabolites a published GCMS method has been adapted. Samples of 200 μl CSF were processed. Following addition of deuterated internal standards and acidification, extraction was carried out with ethyl acetate. Preliminary experiments with the analysis of MHPG using diethyl ether for extraction gave rise to emulsion formation and resulted in poor recoveries for MHPG and in irreproducibility problems due to a preferential extraction of non-labelled MHPG, effects which were not observed with ethyl acetate extraction. Derivatization was done with a mixture of pentafluoropropionic anhydride/pentafluoropropanol (or hexafluoroisopropanol) in order to derivatize both hydroxyl and carboxylic acid groups. The derivatization procedure was optimized for the analysis of 5-HIAA by carrying out a second reaction step with pentafluoropropionic anhydride alone in order to complete the derivatization for the indolic NH moiety. The molecular ions of the derivatized products were selected for detection. The methodology has been applied to evaluate the effects of two α2-antagonists, i.e. yohimbine and idazoxan. Yohimbine was found to increase the CSF levels of the noradrenergic metabolites MHPG and VMA and of the dopaminergic metabolite HVA and to have serotonergic effects, whereas idazoxan was shown to exhibit noradrenergic effect only.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200141119
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  • 5
    Electronic Resource
    Electronic Resource
    Studies in organic mass spectrometry: XVSande, C. Van de; Vandewalle, M. Bull. Soc. Chim. Belges 1973, 82, 775. - mass fragmentographic identification of epinine in adrenal medulla and as a product of an in vitro enzymic methylation (1974)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 1 (1974), S. 103-108 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The presence of epinine in adrenal medulla and in reaction mixtures of enzymic in vitro experiments is proven by mass fragmentography. Derivatization of catecholamines, suitable for gas chromatographic analysis is discussed. The perfluoropropionates were selected for mass fragmentography.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200010204
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  • 6
    Electronic Resource
    Electronic Resource
    Differentiation of 6-C- and 8-C-glycosidic flavonoids by positive ion fast atom bombardment and tandem mass spectrometry (1992)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 21 (1992), S. 213-221 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The present study deals with the use of liquid secondary ion mass spectrometry in combination with collisionally activated dissociation and linked scanning at constant B/E for differentiation and structural analysis of 6-C- and 8-C-glycosidic flavonoids in the positive ion mode. Flavonoids of mono-C-glycosidic nature were investigated. Special emphasis is given to the rationalization of fragment ions which allow differentiation between isomers.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200210406
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  • 7
    Electronic Resource
    Electronic Resource
    Determination of the double bond position in long-chain 6-alkenyl salicylic acids by collisional activation (1993)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 22 (1993), S. 647-653 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The double bond position in long-chain 6-alkenyl salicylic acids has been determined by collisional activation of [M - H + 2Li]+ and [M - H]- precursor ions, which were generated by FAB. The pattern of product ions characteristic for charge-remote fragmentations allowed for a straightforward determination of the location of the double bond for the dilithiated precursor ion species, whereas complications from loss of CO2 were experienced for carboxylate anions. The product ion collisionally activated dissociation spectra obtained for both precursor ion species also reveal the formation of stable radical ions, which are likely distonic and point to the involvement of radical processes in charge-remote fragmentation.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200221105
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  • 8
    Electronic Resource
    Electronic Resource
    Radical processes in remote charge fragmentations of lithium-cationized long-chain alkenyl and alkadienyl salicylic acids (1994)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 23 (1994), S. 20-26 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Multistep radical processes are proposed to rationalize the formation of product ions formed by collisionally induced and spontaneous fragmentation of lithium-cationized 6-alkenyl and 6-alkadienyl salicylic acids. An important step in these processes consists of a homolytic C—H cleavage, a mechanism which is consistent with the charge-remote concept. Evidence is given by the observation that the fragmentation of ions formed by the loss of a hydrogen radical is similar to that found for the precursor [M - H + 2Li]+ ions. The proposed mechanisms also explain very well the observed enhanced abundances of ions whose formation involves formal benzylic, homo-benzylic and homoallylic cleavages. The enhanced abundance of ions whose formation involves formal allylic cleavages can be readily rationalized by resonance stabilization of intermediate allylic radical ions.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200230105
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  • 9
    Electronic Resource
    Electronic Resource
    Fragmentation characteristics of neuropeptides related to chromogranin B and proenkephalin B using fast atom bombardment and collision-induced dissociation (1994)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 23 (1994), S. 603-611 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This study deals with the mass spectral characterization of selected neuropeptides related to chromogranin B and proenkephalin B precursor proteins using fast atom bombardment (FAB) ionization in combination with low- and high-energy collision-induced dissociation. Fragmentation pathways were investigated using linked scan and tandem mass spectrometric techniques. First-order FAB mass spectra and product ion spectra of [M + H]+ ions are discussed and analysed for structure-specific information. In the high-energy production spectra, abundant y and c ions are found to be indicative of the presence of proline and threonine residues, respectively. With regard to side chain specific ions, diagnostic d and w ions are found, which support the presence of leucine, glutamic acid and glutamine at specific positions in the amino acid sequence.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200231002
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  • 10
    Electronic Resource
    Electronic Resource
    Characterization of acylcarnitines using fast atom bombardment mass spectrometry and gas chromatography/mass spectrometry (1995)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 30 (1995), S. 69-80 
    Details
    ISSN: 1076-5174
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Mass spectral data are reported for an extended series of synthesized acylcarnitines. Direct mass spectrometry was performed using ionization by fast atom bombardment in combination with high-energy collisional activation and B/E linked scanning. The data show that it is possible to distinguish between isomeric compounds using this technique. Gas chromatographic/mass spectrometric analysis data for acylcarnitines, as their acyloxylactone derivatives, are reported. Both electron impact and chemical ionization modes were used, permitting the unequivocal characterization and identification of the various compounds. In view of the recent marked increase in acylcarnitine profiling activities, the comprehensively reported mass spectrometric and gas chromatographic data may be useful for reference purposes.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jms.1190300112
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